From patchwork Wed Oct 18 17:41:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 13427612 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C87D4CDB482 for ; Wed, 18 Oct 2023 17:41:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231786AbjJRRlz (ORCPT ); Wed, 18 Oct 2023 13:41:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39338 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231418AbjJRRlq (ORCPT ); Wed, 18 Oct 2023 13:41:46 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6DFB7B0; Wed, 18 Oct 2023 10:41:44 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D83C6C433C8; Wed, 18 Oct 2023 17:41:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697650904; bh=CebfTX8x0gqnWClXdb2PRiRjob3lBToUpb1yn80x07I=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=ixsIePkgd6FqsA4/OTA9y+DP1ZywHc7Sr8eHzCsk+2Jo01xrQdac05wRbts2zVrXc C4o0TOGiSxkweFeCUUdfA+iKlqGX4HQZPPZCWCOKfiWi9Uw2kl/nab5pguFYwqx8Ct qqWZcVRN9CSoC9SWY3fnIJGi+/4qH3kV8pkaapRaJ+RFoTnardz2xPns8JG21g8oJN syy5uIQs3ESM7Q0MoYxYJ4hmMSxmOSV0a5aaoB5lriz1+4wr2V1OVE0iP7JaYyQfkA TtsgJXdaS/oQiTQobkbvyPySWa0MnB33bAbS8srOYejBKAHotOjG8J+z20op4bFNXu WudM7ZkhM2p/Q== From: Jeff Layton Date: Wed, 18 Oct 2023 13:41:12 -0400 Subject: [PATCH RFC 5/9] fs: have setattr_copy handle multigrain timestamps appropriately MIME-Version: 1.0 Message-Id: <20231018-mgtime-v1-5-4a7a97b1f482@kernel.org> References: <20231018-mgtime-v1-0-4a7a97b1f482@kernel.org> In-Reply-To: <20231018-mgtime-v1-0-4a7a97b1f482@kernel.org> To: Linus Torvalds , Alexander Viro , Christian Brauner , John Stultz , Thomas Gleixner , Stephen Boyd , Chandan Babu R , "Darrick J. Wong" , Dave Chinner , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , Amir Goldstein , Jan Kara , David Howells Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, Jeff Layton X-Mailer: b4 0.12.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=3403; i=jlayton@kernel.org; h=from:subject:message-id; bh=CebfTX8x0gqnWClXdb2PRiRjob3lBToUpb1yn80x07I=; b=owEBbQKS/ZANAwAIAQAOaEEZVoIVAcsmYgBlMBjIhGAfiHKR2+BMhUvK9Je6zSTAJVNLPujGV e1DN/iJrxSJAjMEAAEIAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCZTAYyAAKCRAADmhBGVaC FTarEACVylMwhcX6PLK1jzC+Yj+mH5qYypQpchyrOIktUb/AdxXRiWd4sKMRH5DU4sFFxFJHWce 5f8A/LDi2QaJ6fCzZZBK1cfvoc9XAiFCKu3zpxBEmaq++/tX3P2VzqRWTnfE2tgWmG/aUn4Z2tm b2cUog1WhdPXz3ubERRvWNE5WLzgVXFRRtarU/5kEUcrj8ungy2NjdEhUktZQuw8H0+2limB8YS qRrTP47cjY2RtdJA1+X+67DLw+bYymJllU7Db9sEu2CAfCTOMOxO2euB+OHR5wChJas4MjGcc6G WUdoSjOTPlOoiVrGLu9y9zHcC9VUonbBRmRYxTMcIon/aO+1gap4ByfnVvdt0/UhmmD0+lw2wJO G7HUB6PJWXGynG3IpGJorc83Hzi/TSAOc2+zQ/bwZ02IvpHBErXnfh7Nhp7LvyB4nlhJLlvQ43+ TDqOaNj56qR+wFXSFQ83K/wdzpvk1LLbew3buvB1FzEKWdn8RvUU63enQBXlkZ0iUDy3I8dtMUA uWFo0dsHzQMbv6DLYthwF6cJWkmgwEWSCevnwHezl+RA1uT7FSY4RpdjtP99UYzDNh+jqQ6Jbq7 jmJjT0+Lav0EoWH6NwVtw+QqAPT+fxHW3d5Q91P12s38P2PtFjUndb2Rf7IXNKwdcJV9mgtdc+3 9sLsvNrKr7s47Jg== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org The setattr codepath is still using coarse-grained timestamps, even on multigrain filesystems. To fix this, we need to fetch the timestamp for ctime updates later, at the point where the assignment occurs in setattr_copy. On a multigrain inode, ignore the ia_ctime in the attrs, and always update the ctime to the current clock value. Update the atime and mtime with the same value (if needed) unless they are being set to other specific values, a'la utimes(). Note that we don't want to do this universally however, as some filesystems (e.g. most networked fs) want to do an explicit update elsewhere before updating the local inode. Signed-off-by: Jeff Layton --- fs/attr.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 46 insertions(+), 6 deletions(-) diff --git a/fs/attr.c b/fs/attr.c index bdf5deb06ea9..1d3e6f562bec 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -275,6 +275,42 @@ int inode_newsize_ok(const struct inode *inode, loff_t offset) } EXPORT_SYMBOL(inode_newsize_ok); +/** + * setattr_copy_mgtime - update timestamps for mgtime inodes + * @inode: inode timestamps to be updated + * @attr: attrs for the update + * + * With multigrain timestamps, we need to take more care to prevent races + * when updating the ctime. Always update the ctime to the very latest + * using the standard mechanism, and use that to populate the atime and + * mtime appropriately (unless we're setting those to specific values). + */ +static void setattr_copy_mgtime(struct inode *inode, const struct iattr *attr) +{ + unsigned int ia_valid = attr->ia_valid; + struct timespec64 now; + + /* + * If the ctime isn't being updated then nothing else should be + * either. + */ + if (!(ia_valid & ATTR_CTIME)) { + WARN_ON_ONCE(ia_valid & (ATTR_ATIME|ATTR_MTIME)); + return; + } + + now = inode_set_ctime_current(inode); + if (ia_valid & ATTR_ATIME_SET) + inode_set_atime_to_ts(inode, attr->ia_atime); + else if (ia_valid & ATTR_ATIME) + inode_set_atime_to_ts(inode, now); + + if (ia_valid & ATTR_MTIME_SET) + inode_set_mtime_to_ts(inode, attr->ia_mtime); + else if (ia_valid & ATTR_MTIME) + inode_set_mtime_to_ts(inode, now); +} + /** * setattr_copy - copy simple metadata updates into the generic inode * @idmap: idmap of the mount the inode was found from @@ -307,12 +343,6 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, i_uid_update(idmap, attr, inode); i_gid_update(idmap, attr, inode); - if (ia_valid & ATTR_ATIME) - inode_set_atime_to_ts(inode, attr->ia_atime); - if (ia_valid & ATTR_MTIME) - inode_set_mtime_to_ts(inode, attr->ia_mtime); - if (ia_valid & ATTR_CTIME) - inode_set_ctime_to_ts(inode, attr->ia_ctime); if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; if (!in_group_or_capable(idmap, inode, @@ -320,6 +350,16 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, mode &= ~S_ISGID; inode->i_mode = mode; } + + if (is_mgtime(inode)) + return setattr_copy_mgtime(inode, attr); + + if (ia_valid & ATTR_ATIME) + inode_set_atime_to_ts(inode, attr->ia_atime); + if (ia_valid & ATTR_MTIME) + inode_set_mtime_to_ts(inode, attr->ia_mtime); + if (ia_valid & ATTR_CTIME) + inode_set_ctime_to_ts(inode, attr->ia_ctime); } EXPORT_SYMBOL(setattr_copy);